Dry-bulk tanker, conveying system for a dry-bulk tanker, as well as work train

ABSTRACT

A dry-bulk tanker for the provision of binding agents for soil stabilization for a spreading device comprises a storage container (10) for binding agent. A mechanical conveying device (18) for conveying binding agents from the storage container (10) into an intermediate chamber (20) is connected to the storage container (10). A pneumatic conveying device (36) for conveying the binding agent to the spreading device is connected to the intermediate chamber (20). A pressure relief device (40, 41) is connected to the mechanical conveying device in order to avoid the entry of compressed air into the storage container (10). The invention furthermore relates to a conveying system for a dry-bulk tanker and to a work train for working soils with a self-propelled ground working machine and a dry-bulk tanker.

BACKGROUND OF THE INVENTION 1. Field of the Invention

The invention relates to a dry-bulk tanker for the provision of bindingagents for soil stabilization for a spreading device, as well as to aconveying system for a dry-bulk tanker. Furthermore, the inventionrelates to a work train for working soils with a self-propelled groundworking machine and a dry-bulk tanker.

2. Description of the Prior Art

An improvement or stabilization of soils can be effected in particularby means of dry binding agent such as, for example, lime or cement. Tothis end, the binding agent is introduced into the soil in order to, inparticular, increase the loadbearing capacity of the same. Soilstabilization is performed in particular in the construction of roads orrailway lines, as well as in the construction of industrial sites.

Binding agent spreaders are known for the purpose of spreading bindingagent. Such vehicles comprise a large container for the reception ofbinding agent. The spreading of binding agent is effected in such afashion that the spreading vehicle drives ahead of the stabilizer orrecycler. An upper layer of a surface to be stabilized is milled off bythe stabilizer or recycler by means of, for example, a milling/mixingdrum, the milled-off material is optionally mixed with further material,and spread again. The binding agent spread by the binding agent spreaderahead of the stabilizer or recycler is also picked up as part of thisprocess. It is of disadvantage with such binding agent spreaders drivingahead that the binding agent may drift. This increases the costs as aresult of the increased material requirement and leads to dust exposurefor the workers and residents.

Moreover, stabilizers and recyclers are known which comprise a bindingagent spreader. Such stabilizer or recycler with integrated bindingagent spreader is known, for example, from DE 10 2009 008 884 (U.S. Pat.No. 8,511,933). It is hereby possible for the binding agent to bespread, for example, directly ahead of the milling/mixing rotor so thatthe binding agent is picked up immediately by the milling/mixing rotor.In this process, there is no hazard of drifting. On the other hand, suchstabilizers or recyclers with integrated binding agent container havethe disadvantage that such binding agent container has a small fillingvolume and must therefore be filled regularly. The filling of suchbinding agent container is effected by means of a dry-bulk tanker.Binding agent is fed from the dry-bulk tanker to the binding agentcontainer of the stabilizer or recycler at regular intervals. Feeding iseffected, for example, pneumatically. To this end, the binding agentcontainer of the dry-bulk tanker is pressurized for the filling process.Filling the container of the stabilizer or recycler while driving ispossible to a limited extent only.

A work train comprising a dry-bulk tanker and a milling vehicle is knownfrom DE 20 2008 012 104. The milling vehicle comprises a storagecontainer for dry bulk material such as a binding agent. Said containerfeatures a small volume and is, insofar, filled permanently by thedry-bulk tanker. In this arrangement, the dry-bulk tanker is designed insuch a fashion that it is not necessary to pressurize the entire bindingagent container of the dry-bulk tanker. Rather, a mechanical transportdevice is arranged inside the binding agent container of the dry-bulktanker which conveys the dry bulk material into a chamber by means of,for example, a conveying screw. From the chamber, the dry bulk materialis thereupon conveyed to the storage container of the milling vehiclepneumatically via a transport line. However, it is of disadvantage inthis design that, due to the pneumatic conveying process, a swirling ofthe binding agent takes place also inside the binding agent container ofthe dry-bulk tanker. This may lead to an inconsistent feed of bindingagent to the storage container of the milling vehicle. Furthermore,there is the disadvantage that an increased dust development occursinside the dry-bulk tanker. This leads to higher loads of the filtersystems and may furthermore also give rise to malfunctions of sensors,in particular, of filling level sensors arranged inside the dry-bulktanker.

SUMMARY OF THE INVENTION

The object of the invention is to create a dry-bulk tanker for theprovision of binding agent for soil stabilization for a spreading devicewith which a reliable feed of binding agent is possible, as well as tocreate a corresponding work train.

The object according to the present invention is achieved by a dry-bulktanker, a conveying system for a dry-bulk tanker, and a work train forworking soils such as roads, railway lines, industrial sites etc. bymeans of a ground working machine and a dry-bulk tanker as disclosedherein.

The dry-bulk tanker is used, in particular, to fill a binding agentcontainer of a ground working machine, such as a stabilizer or recycler,as described, for example, in DE 10 2009 008 884 (8,511,933). Thedry-bulk tanker according to the present invention for the provision ofbinding agent for soil stabilization for a spreading device comprises astorage container for the binding agent. A mechanical conveying deviceis connected to the storage container. The binding agent is conveyedfrom the storage container into an intermediate chamber by means of theconveying device. A pneumatic conveying device is connected to theintermediate chamber. The binding agent is conveyed to the spreadingdevice by means of the pneumatic conveying device, wherein the spreadingdevice comprises, in particular, a storage container or intermediatebuffer, respectively. The spreading device is specified, in particular,directly on a ground working machine. According to the presentinvention, a pressure relief device is connected to the mechanicalconveying device. An entry of compressed air into an area of the storagecontainer of the dry-bulk tanker in which a swirling-up of the bindingagent in the storage container of the dry-bulk tanker would interferewith a reliable conveying process is essentially avoided by means of thepressure relief device.

The pressure relief device may be a valve connected to the mechanicalconveying device. Pressure possibly forming in the mechanical conveyingdevice may be reduced or compressed air discharged, respectively, viathe valve. The compressed air in question may be immediately dischargedinto the environment, wherein it is preferred for a filter device to bespecified in order to prevent an escape of binding agent. In particularwhen specifying a filter device, it is not necessarily required toadditionally specify a valve. A corresponding discharge opening in themechanical conveying device through which the compressed air can escapeis sufficient.

The mechanical conveying device is, for example, a gravity conveyor. Inthis design, conveying of the binding agent may be effected, inparticular, based on the own weight, wherein conveying of the bindingagent may also be assisted, for example, by a screw conveyor or thelike.

In order to prevent a swirling-up of spreading agent as a result of thecompressed air entering the storage container of the dry-bulk tanker inan area causing swirl-ups such as, in particular, in the area of theremoval of the spreading agent, it is particularly preferred for themechanical conveying device to comprise a conveying chamber. In thisarrangement, a conveying device may be designed, for example, accordingto an airlock. An opening to the storage container may thus be openedand closed via corresponding slide gates, and a connection between theconveying chamber and the intermediate chamber may be opened and closedvia additional slide gates. Analogous to an airlock, the conveyingchamber may thus be initially filled with binding agent from the storagecontainer by opening the relevant slide gate, wherein the slide gate isthereupon closed prior to the slide gate closing the opening to theintermediate chamber being opened. As a result of this, nothing butpressure ever enters the conveying chamber from the intermediatechamber. According to the present invention, the conveying chamber isthereupon connected to the pressure relief device so that the pressurein the conveying chamber may be reduced prior to the airlock beingconnected to the storage container again, for the purpose of fillingwith binding agent, by operating the relevant slide gate.

In a particularly preferred embodiment, the mechanical conveying deviceis a rotary feeder. Said rotary feeder comprises, in particular, aplurality of conveying chambers arranged about an axis of rotation.Binding agent enters a conveying chamber open in the direction of thestorage container by way of gravity or by means of a further conveyingdevice. The respective conveying chamber is thereupon rotated further bythe rotary feeder until the binding agent in the respective chambercontinues from the same into the intermediate chamber due to gravity.With the aid of a rotary feeder, it is possible, in particular, torealize a continuous conveying of binding agent from a plurality ofconveying chambers arranged about an axis of rotation. Compressed airenters a conveying chamber connected to the intermediate chamber, or thepressure in said conveying chamber increases, respectively. Prior tosaid conveying chamber being connected to the storage container again, areduction of pressure in said conveying chamber is achieved by means ofthe pressure relief device. To this end, the connection of therespective conveying chamber to the intermediate chamber is interruptedduring the further rotation of the rotary feeder. The pressure reductionis effected in this position.

Independent of the type of conveying device used, it is thereforeparticularly preferred for the pressure relief device to be arranged inan area in which a conveying chamber passing through this area isconnected neither to the storage container nor to the intermediatechamber.

In a preferred development of the pressure relief device, the same isconnected to the storage container by means of a vent line. The pressurerelief device may be formed merely by the connection of the mechanicalconveying device to the storage container via a vent line. In addition,a valve may be optionally specified in the vent line. The vent line ispreferably connected to an area of the storage container in which theintroduction of air does either not cause any swirl-ups of binding agentor the same are non-disturbing. The introduction of the compressed airinto the storage container is preferably effected in an upper area ofthe storage container and/or an area of the storage container remotefrom the mechanical conveying device.

The storage container preferably comprises a positive pressure outlet.Said positive pressure outlet preferably comprises a filter device inorder to avoid an escape of binding agent. In a preferred development,the vent line of the pressure relief device is, in particular, directlyconnected to the positive pressure outlet. An occurrence of swirl-upsinside the storage container is thereby avoided.

For conveying the binding agent from the intermediate chamber to thespreading device, it is preferred for the pneumatic conveying device tocomprise a compressed air source, in particular, a compressor. Thecompressor is connected to the intermediate chamber either directly orvia a pressure line. The use of a compressor as a pneumatic conveyingdevice has the advantage that, on the one hand, faster conveying of thebinding agent from the intermediate chamber to the spreading device canbe realized as a result, and, on the other hand, such compressor isusually present in dry-bulk tankers in particular for cleaning purposes.

In a further preferred embodiment, the storage container of the dry-bulktanker is connected to a plurality of mechanical conveying devices.Preferably, a plurality of separate intermediate chambers are optionallyspecified, wherein each intermediate chamber is optionally connected toa separate mechanical conveying device. In particular, each mechanicalconveying device comprises a separate pressure relief device.

When providing a plurality of intermediate chambers, these arepreferably arranged in series with respect to the pneumatic conveyingprocess. In a preferred embodiment, the binding agent is thus conveyed,for example, from a first intermediate chamber into a secondintermediate chamber in a first step, and thereupon from said secondintermediate chamber to the spreading device. Furthermore, it is alsopossible to arrange a plurality of intermediate chambers parallel to oneanother.

In a preferred development of the present invention, the dry-bulk tankerfurthermore comprises a pneumatic bypass line bypassing the at least oneintermediate chamber. Said bypass line branches off, on the one hand, inparticular, from the pressure line, that is, the line between thecompressed air source and the intermediate chamber, and is, on the otherhand, connected to the conveying line, that is, the line that leads fromthe at least one intermediate chamber to the spreading device. It isthus possible to generate a higher flow of compressed air or higherpressure, respectively, in the conveying line, and consequently ensuresafe feeding of a binding agent to the spreading device. When specifyinga plurality of intermediate chambers, the bypass line may optionallyalso bridge a single intermediate chamber only. Furthermore, a pluralityof bypass lines is also possible, each of which bridges a single or aplurality of intermediate chambers. Branches are also possible in abypass line bridging a plurality of intermediate chambers, which isthereupon connected to a line that connects two neighbouringintermediate chambers. The single bypass line or plurality of bypasslines may preferably be partially or wholly disconnectable orcontrollable, respectively, so that it is possible to distribute theamount of compressed air that is conducted through the at least oneintermediate chamber or through the at least one bypass line,respectively. It is understood that different bypass lines and/orbranches of the bypass lines may each be provided with separatelycontrollable valves.

The invention furthermore relates to a conveying system for a dry-bulktanker. This is a separate invention which, in a preferred development,is suitable in particular for the dry-bulk tanker described above. Theconveying system according to the present invention comprises amechanical conveying device for conveying binding agent. Furthermore,the conveying system comprises at least one intermediate chamber for thereception of the binding agent conveyed by the conveying device. Apneumatic conveying device is connected to the intermediate chamber inorder to convey the binding agent to a spreading device. In this design,the spreading device is not a component part of the conveying system butpart of a separate vehicle or a separate device and, in particular,component part of a self-propelled ground working machine. According tothe present invention, the conveying system comprises a pressure reliefdevice which is connected to the mechanical conveying device. Thepressure relief device according to the present invention features theadvantages described above with reference to the dry-bulk tanker,wherein, in particular, an entry of compressed air into an area of astorage container of the dry-bulk tanker is avoided by means of thepressure relief device when the conveying system is connected to arelevant dry-bulk tanker.

The individual constructional elements of the conveying system areadvantageously developed as described above with reference to thedry-bulk tanker. In a particularly preferred embodiment, the mechanicalconveying device is, in particular, designed as a gravity conveyor. Itis furthermore preferred for the mechanical conveying device to compriseconveying chambers and to be preferably designed as a rotary feeder. Itis additionally preferred for the pressure relief device to be connectedto the mechanical conveying device in an area in which a conveyingchamber passing through said area is connected neither to the storagecontainer of the dry-bulk tanker nor to the at least one intermediatechamber.

As likewise described above in a preferred development with reference tothe dry-bulk tanker, it is preferred for the pneumatic conveying deviceto comprise a compressor which is connected to the at least oneintermediate chamber, in particular, via a pressure line. This may be acompressor already specified on the dry-bulk tanker. Furthermore, it islikewise preferred for each mechanical conveying device to be connectedto a separate intermediate chamber provided that a plurality ofconveying devices is specified. When specifying a plurality ofintermediate chambers, it is furthermore preferred for the intermediatechambers to be arranged in series with respect to the pneumaticconveying device. Furthermore, it is possible for a pneumatic bypassline bypassing the at least one intermediate chamber to be specified,which is connected to the conveying line for feeding the binding agentto the spreading device.

The invention furthermore relates to a work train for working soilswhich are, for example, roads, railway lines, industrial sites, or thelike. The work train comprises an, in particular, self-propelled groundworking machine such as a stabilizer or recycler. The ground workingmachine comprises a milling/mixing rotor inside a rotor housing.Furthermore, the ground working machine comprises a spreading device forspreading binding agent. The spreading device is connected to thedry-bulk tanker so that binding agent can be fed from the dry-bulktanker to the spreading device in particular during the operation. Inthis arrangement, the dry-bulk tanker is designed as described above andpreferably advantageously developed. The spreading device preferablycomprises a buffer container for binding agent, wherein the buffercontainer is thereupon connected to the dry-bulk tanker or the at leastone intermediate chamber, respectively, via the conveying line. Themaximum conveying rate of the binding agent in the conveying line, whichis connected to the buffer container of the ground working machine, ispreferably no less than 400 kg/min and, in particular, no less than 550kg/min. The conveying volume is adjustable, in particular, to therequirements or consumption, respectively.

Filling of the buffer container is preferably controlled from the groundworking machine. This may be effected, for example, by means ofappropriate filling level sensors in the buffer container. In thisarrangement, filling of the buffer container may be effectedcontinuously or intermittently.

BRIEF DESCRIPTION OF THE DRAWINGS

Based on a preferred embodiment, the invention is hereinafterillustrated in more detail with reference to the enclosed drawings.

The following is shown:

FIG. 1: a schematic rear view of a dry-bulk tanker,

FIG. 2: a schematic sectional view along line II-II in FIG. 1, and

FIG. 3 a schematic side view of a ground working machine.

DETAILED DESCRIPTION

The dry-bulk tanker comprises a storage container 10 for binding agent.The storage container 10 comprises, on an underside 12, two openings 14which, in the embodiment presented, are connected, via a funnel element16 each, to a mechanical conveying device 18 each, wherein, in theembodiment presented, the conveying devices 18 are rotary feeders. Therotary feeders 18 are each connected to an intermediate chamber 20. Themechanical conveying devices 18 may also be referred to as mechanicalconveyors 18.

From the storage container 10, binding agent enters the funnel elements16 through the openings 14. This is effected, in particular, by means ofgravity, wherein a mechanical conveying device, such as a screw conveyoror the like, may optionally be additionally specified in the storagecontainer, for example, to transport the binding agent to the opening 14from an end of the storage container 10 remote from the opening 14. Thebinding agent slides through the funnel devices 16 into an upperconveying chamber which is in position 24 (FIG. 2) of the rotary feeder18. The rotary feeder 18 rotates about an axis 22 in FIG. 2 in thedirection of arrow 25. Thus, after the chamber in position 24 that iscurrently filled with binding agent, the chambers in positions 34 and 32will be filled with binding agent. From the conveying chamber inposition 30, which is arranged opposite the conveying chamber inposition 24, the binding agent enters the intermediate chamber 20 due togravity. The two conveying chambers in positions 32 and 34, followingbehind the conveying chamber in position 30 as seen in the direction ofrotation 25, are empty. The conveying chambers in positions 26 and 28have already been filled with binding agent and are emptied into theintermediate chamber 20 successively with the continued rotation of therotary feeder 18 in the direction of arrow 25.

For pneumatic conveying of the binding agent, compressed air isintroduced into the intermediate chamber 20 by means of a conveyingdevice which, in the embodiment presented, is a compressor 36. There istherefore an increased pressure in the intermediate chambers 20 comparedto the environment. Compressed air enters the first intermediate chamber20 as seen in conveying direction via the pressure line 38 connected tothe compressor 36. Since the first intermediate chamber 20 as seen inconveying direction is connected to the second intermediate chamber 20as seen in conveying direction via a connecting line 46, there isincreased pressure also in said second intermediate chamber 20. Therelevant compressed air also enters the conveying chamber of the rotaryfeeder 18 that is in position 30. There is therefore an increasedpressure in the chamber in position 32. The pressure in the chamber inposition 34, which is initially also increased, is carried off via apressure relief device. In the embodiment presented, the pressure reliefdevice comprises at least one channel or one line 40 which is connectedto an area of the mechanical conveying device 18 in which the emptiedconveying chamber, for example, in the area of position 34, is connectedneither to the intermediate chamber 20 nor to the storage container 10.A valve 41, in particular, a non-return valve, may be optionallyspecified in the line 40 in particular in the area in which the line 40is connected to the rotary feeder 18. The area of position 34 seen inFIG. 2 may be referred to as an isolated area.

Since residual amounts of binding agent may still be present in thechamber in position 34, these may enter the pressure relief device 40,41. The pressure relief device 40, 41 is therefore connected to thestorage container 10 so that any binding agent present in the line 40 isconveyed back into the storage container 10. In order to avoid theformation of positive pressure in the storage container 10, the storagecontainer 10 comprises a positive pressure outlet 44 connected to afilter 42. In order to avoid a swirling of binding agents in the storagecontainer 10, the line 40 is connected to the same in an upper area ofthe storage container 10.

For conveying the binding agent to the spreading device or to a buffercontainer 52 (FIG. 3) of the spreading device, respectively, pressurizedair is fed, by means of the compressor 36, to the first intermediatechamber 20 as seen in conveying direction via the pressure line 38. Thefirst intermediate chamber 20 is connected to the second intermediatechamber 20 as seen in the direction of flow via the connecting line 46so that binding agent is conveyed from the first intermediate chamber 20into the second intermediate chamber 20 through the connecting line 46.The second intermediate chamber 20 as seen in the direction of flow isconnected to the spreading device or the buffer container 52 of thespreading device, respectively, via a conveying line 48.

Furthermore, a bypass line 50 bridging the two intermediate chambers 20is connected to the pressure line 38 upstream of the first intermediatechamber 20 as seen in the direction of flow, and is connected to theconveying line 48 downstream of the second intermediate chamber 20 asseen in the direction of flow. The bypass line 50 is connected to theconnecting line 46 via a branching line 51. For control of thedistribution of the compressed air, an in particular controllable valvemay be arranged, for example, in the bypass line 50 and/or in thebranching line.

Depending on the design, the pneumatic conveying device thereforecomprises a compressed air source which, in the embodiment presented, isa compressor 36, and lines. In addition to the compressed air line 38,the pneumatic conveying device may comprise the lines 46, 50, 51 and 48.The pneumatic conveying device may also be referred to as a pneumaticconveyor.

For conveying the binding agent, pressure is applied to the pneumaticconveying device from a pressure source which, in the embodiment, is thecompressor 36. This leads to increased pressure in the conveying devicecompared to the environment. For transferring the binding agent from theconveying chambers into the intermediate container 20, the conveyingchambers are connected, in an air-permeable fashion, to the intermediatecontainer 20 and thus to the pneumatic conveying device exhibiting apositive pressure compared to the environment. In the embodimentpresented, there is therefore an increased air pressure compared to theenvironment also in the conveying chambers in positions 30 and 32. Inthe conveying chamber in position 30, there is an increased air pressuredue to the currently present air-permeable connection to the pneumaticconveying device. In the conveying chamber in position 32, the pressurewas increased when the same was connected to the intermediate chamber 20in an air-permeable fashion for the discharge of binding agent. With thecontinued rotation of the rotary airlock 18, said air-permeableconnection was interrupted; the pressure present can, however, not bereduced. According to the present invention, the pressure relief device40, 41 is specified in position 34 of the mechanical conveying device18.

The dry-bulk tanker 54 presented in FIG. 2 is connected to the groundworking machine 56 presented in FIG. 3 via the conveying line 48. Theground working machine 56 comprises the buffer container 52 which isconnected to the conveying line 48 and is used for the intermediatebuffering of binding agent. A spreading device 58 not presented infurther detail is connected to the buffer container 52. Binding agent isspread on a surface 60 of a ground to be milled-off, such as a roadsurface, via the spreading device 58. The surface 60 is thereuponremoved by means of a milling and mixing rotor 62. Such ground workingmachine with buffer container 52 is described, for example, in DE 102009 008 884.

1-16. (canceled) 17: A dry-bulk tanker for the provision of bindingagent for soil stabilization to a spreading device, the dry-bulk tankercomprising: a storage container for the binding agent; at least oneintermediate chamber; at least one mechanical conveyor configured toconvey the binding agent from the storage container to the at least oneintermediate container; a pneumatic conveyor configured to convey thebinding agent from the at least one intermediate chamber to thespreading device; and a pressure relief device connected to the at leastone mechanical conveyor, the pressure relief device including a ventline connected to the storage container. 18: The dry-bulk tanker ofclaim 17, wherein: the at least one mechanical conveyor comprises agravity conveyor. 19: The dry-bulk tanker of claim 17, wherein: the atleast one mechanical conveyor comprises a rotary feeder including aplurality of conveying chambers. 20: The dry-bulk tanker of claim 17,further comprising: a positive pressure outlet communicated with thestorage container; and a filter configured to prevent binding agent frompassing through the positive pressure outlet. 21: The dry-bulk tanker ofclaim 20, wherein: the vent line of the pressure relief device iscommunicated with the positive pressure outlet. 22: The dry-bulk tankerof claim 17, wherein: the pneumatic conveyor includes a compressor and apressure line connecting the compressor to the at least one intermediatechamber. 23: The dry-bulk tanker of claim 17, wherein: the at least onemechanical conveyor includes at least two mechanical conveyorsconfigured to convey the binding agent from the storage container to theat least one intermediate chamber. 24: The dry-bulk tanker of claim 23,wherein: the at least one intermediate chamber includes at least twointermediate chambers; and each of the at least two mechanical conveyorsis connected to a separate one of the at least two intermediatechambers. 25: The dry-bulk tanker of claim 24, wherein: the at least twointermediate chambers are arranged in series with respect to thepneumatic conveyor. 26: The dry-bulk tanker of claim 17, wherein: thepneumatic conveyor includes a conveying line configured to feed thebinding agent from the at least one intermediate chamber to thespreading device, and the pneumatic conveyor includes a pneumatic bypassline bypassing the at least one intermediate chamber and connected tothe conveying line. 27: A work train for working soils, the work traincomprising: a self-propelled ground working machine including a millingor mixing rotor arranged in a rotor housing, and including a spreadingdevice for spreading binding agent; and a dry-bulk tanker including: astorage container for the binding agent; at least one intermediatechamber; at least one mechanical conveyor configured to convey thebinding agent from the storage container to the at least oneintermediate container; a pneumatic conveyor configured to convey thebinding agent from the at least one intermediate chamber to thespreading device; and a pressure relief device including a vent linecommunicated with the at least one mechanical conveyor and communicatedwith the storage container. 28: The work train of claim 27, wherein: thespreading device includes a buffer container for the binding agent; andfurther comprising a conveying line connecting the pneumatic conveyor tothe buffer container.